title: Role of versicolorin A and its derivatives in aflatoxin biosynthesis.
abstract: The involvement of various anthraquinone metabolites in the biosynthesis of aflatoxin B1 was investigated by using a labeled double-substrate technique in a cell-free system. The results showed that both versicolorin A hemiacetal and versicolorin A hemiacetal acetate were converted to aflatoxin B1, whereas versicolorin A was not, even though it was added to the same cell-free system. Thus, versicolorin A hemiacetal, versicolorin A hemiacetal acetate, or both were implicated as key intermediates, whereas versicolorin A and C became side shunt metabolites. These latter compounds reentered the pathway depending on the availability of the appropriate enzymes and suitability of conditions. Dichlorvos, a specific inhibitor of aflatoxin biosynthesis, is considered to have its primary action on either an oxygenase or dehydrogenase involved in the pathway and to act in a secondary capacity as an inhibitor of an esterase which may also be involved in the pathway.
mesh_terms: D016604:Aflatoxin B1; D000348:Aflatoxins / Q000096:biosynthesis*; D000880:Anthraquinones / Q000378:metabolism*; D001231:Aspergillus flavus / Q000378:metabolism*; D002250:Carbon Radioisotopes; D011865:Radioisotope Dilution Technique; D014316:Tritium
chemical_list: D000348:Aflatoxins; D000880:Anthraquinones; D002250:Carbon Radioisotopes; D014316:Tritium; C005888:versicolorins; D016604:Aflatoxin B1